Department of Civil and Environmental Engineering, Tufts University, Medford, MA 02155, USA.
Acta Trop. 2011 May;118(2):123-7. doi: 10.1016/j.actatropica.2011.02.006. Epub 2011 Feb 24.
Two screening methods, reagent dipsticks for hematuria and urine filtration for Schistosoma haematobium eggs, were evaluated for their sensitivity and specificity in diagnosing infection with S. haematobium in lightly infected Ghanaian children. Schoolchildren aged 8-18 years (n=255) provided urine samples on three occasions. Overall, 36.4% of girls and 50.7% of boys presented with eggs at least once; 3.3% of girls and 7.5% of boys presented with both eggs and hematuria three times. Many children presented with eggs but without hematuria, or with hematuria but without eggs. When each child was screened three times, the sensitivity of each test method improved by at least 22.9% as compared with single screening, but previously unidentified infections were detected at the third screening, indicating that even three screenings is insufficient. Nearly half of lightly infected children (<50 eggs/10 ml urine, by maximum egg count) were egg-positive during only one of three screenings. Thus, data presented here indicate that when individuals are screened repeatedly, infection status can be assessed more accurately, control programs can be properly evaluated, and population estimates of S. haematobium infection may be made with increased confidence, as compared with single screening.
两种筛查方法，即尿液潜血试剂条和尿沉渣找埃及血吸虫卵，用于评估其在轻度感染加纳儿童中诊断埃及血吸虫感染的敏感性和特异性。255 名 8-18 岁的在校学生分三次提供尿液样本。总体而言，36.4%的女孩和 50.7%的男孩至少有一次出现了虫卵；3.3%的女孩和 7.5%的男孩三次都出现了虫卵和血尿。许多儿童出现了血尿但没有虫卵，或出现了虫卵但没有血尿。当每个孩子被筛查三次时，与单次筛查相比，每种检测方法的敏感性至少提高了 22.9%，但在第三次筛查中发现了以前未识别的感染，表明即使进行三次筛查也不够。在仅有一次筛查中，近一半轻度感染的儿童（最大虫卵计数 <50 个/10ml 尿液）呈阳性。因此，这里提供的数据表明，与单次筛查相比，当个体反复筛查时，可以更准确地评估感染状况，可以更好地评估控制计划，并且可以更有信心地进行埃及血吸虫感染的人群估计。
